This invention relates generally to gas turbine engines, and more specifically to methods and apparatus for operating gas turbine engines.
Gas turbine engines generally include, in serial flow arrangement, a high-pressure compressor for compressing air flowing through the engine, a combustor in which fuel is mixed with the compressed air and ignited to form a high temperature gas stream, and a high pressure turbine. The high-pressure compressor, combustor and high-pressure turbine are sometimes collectively referred to as the core engine. Such gas turbine engines also may include a low-pressure compressor, or booster, for supplying compressed air to the high pressure compressor.
Gas turbine engines are used in many applications, including in aircraft, power generation, and marine applications. The desired engine operating characteristics vary, of course, from application to application. Accordingly, at least one known gas turbine includes a booster compressor to facilitate increasing the pressure of the air entering the high pressure compressor, which results in increased power output and efficiency of the gas turbine engine. An intercooler heat exchanger may be positioned between the booster compressor and the high-pressure compressor to facilitate reducing the temperature of the air entering the high-pressure compressor. Using an intercooler facilitates increasing the efficiency of the engine while reducing the quantity of work performed by the high pressure compressor. Moreover, at least one known intercooler heat exchanger uses water as a cooling medium to cool the air flow exiting the booster compressor. When water is used as the cooling medium, heat from the water is rejected using water cooled cooling towers. The intercooler system rejects substantially all of the heat generated from the intercooler into the atmosphere. Accordingly, the heat rejected by the intercooler is not captured and thus not utilized for any beneficial purpose.